I haven't looked at my computer recently (as its all in storage until when I set everything up), but its a 2009 Mac Pro (tower), 3.6ghz, 32gb ram, solid state boot with other hdd's. I'm upgrading graphics card that can run 4 visual outs. There is nothing 'extra' in it really.

I'll be buying ProTools HD (just one year subscription for now). The reason I want to buy HD is simply because of the 5.1 capabilities - which I'll be making heavy use of. I've been using the C|24 surface for several years and Pro-Tools HD - however its been in someone else studio where I've just walked in, plugged in my hdd and used - so the equipment/hardware side I've not fully known, only the surface and software.

I'll happily buy other gear, especially for a better sound, but essentially I want to run 16 individual mics into PT's.
I was looking at the ''Apogee Symphony I/O MKII Thunderbolt 16x16 Analog I/O'' - this is an expensive piece of kit, i know, but would this work? I've heard great things about Apogee - so maybe worth the investment if this is the only piece of equipment I'll be needing. If I used other outboard equipment, would all the controls on the surface be the same (gain control when tracking etc)?

I bought the C|24 because I know the desk better than the back of my hand (in terms of working with speed and ease) and because it was just under 3,000. Which I thought was very cheap for it.